Display device and electrical device using the same

ABSTRACT

A display device includes: a substrate comprising a first region and a second region bent relative to the first region; a plurality of first pixels at the first region, each of the first pixels comprising a first light-emitting diode (LED), the first LED comprising a pixel electrode, an emission layer for emitting light of a first color, and a counter electrode; a plurality of second pixels at the second region, each of the second pixels comprising a second LED, the second LED comprising a pixel electrode, an emission layer configured to emit the first color, and a counter electrode; and an optical resonance layer at the second region corresponding to the second LED.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2015-0024238, filed on Feb. 17, 2015, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein in its entirety by reference.

BACKGROUND

1. Field

Aspects of one or more embodiments of the present invention relate to adisplay device and an electrical device using the display device.

2. Description of the Related Art

Recently, in addition to the effort to provide electronic devices in avariety of configurations, research and development is underway forproviding displays in various configurations to be mounted on electronicdevices.

Organic light-emitting display devices, which are self-emission displaydevices, have attracted attention as next generation display devices interms of being driven at a relatively low voltage without requiring aseparate light source, being formed as relatively thin and lightweightdevices, and having high-quality characteristics, such as wide viewingangles, high contrast ratios, and excellent response speed.

It is to be understood that this Background of the technology section isintended to provide useful background for understanding the technologyand as such disclosed herein, the Background section may include ideas,concepts, or information that do not constitute prior art.

SUMMARY

One or more example embodiments of the present invention include adisplay device and an electrical device using the display device.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to some example embodiments of the present invention, adisplay device includes: a substrate comprising a first region and asecond region bent relative to the first region; a plurality of firstpixels at the first region, each of the first pixels comprising a firstlight-emitting diode (LED), the first LED comprising a pixel electrode,an emission layer for emitting light of a first color, and a counterelectrode; a plurality of second pixels at the second region, each ofthe second pixels comprising a second LED, the second LED comprising apixel electrode, an emission layer configured to emit the first color,and a counter electrode; and an optical resonance layer at the secondregion corresponding to the second LED.

The optical resonance layer may be between the pixel electrode of thesecond LED and the counter electrode of the second LED.

The counter electrode of the first LED may be integrally formed with thecounter electrode of the second LED to cover the first region and thesecond region of the substrate.

Each of the first LED and the second LED may further include at leastone functional layer between the pixel electrode and the counterelectrode of each of the first LED and the second LED, and the at leastone functional layer corresponding to the first LED may be integrallyformed with the at least one functional layer corresponding to thesecond LED.

A first height from the pixel electrode of the first LED to the emissionlayer of the first LED may be smaller than a second height from thepixel electrode of the second LED to the emission layer of the secondLED.

A thickness of the optical resonance layer may be equal to a differencebetween the first height and the second height.

Each of the first LED and the second LED may further include a firstresonance auxiliary layer between the pixel electrode of each of thefirst LED and the second LED and the emission layer may be configured toemit light of the first color of each of the first LED and the secondLED.

Each of the plurality of first pixels may further include a third LEDconfigured to emit light of a second color, each of the plurality ofsecond pixels may further include a fourth LED configured to emit lightof the second color, and the optical resonance layer may be at thesecond region to correspond to the second LED and the fourth LED.

Each of the third LED and the fourth LED may further include a secondresonance auxiliary layer between a pixel layer of each of the third andfourth LEDs and an emission layer configured to emit light of the secondcolor of each of the third and fourth LEDs.

Each of the first LED and the second LED may further include the firstresonance auxiliary layer between the pixel electrode of each of thefirst LED and the second LED and the emission layer may be configured toemit light of the first color of each of the first LED and the secondLED, and a thickness of the first resonance auxiliary layer may bedifferent from a thickness of the second resonance auxiliary layer.

Each of the plurality of first pixels may further include a fifth LEDconfigured to emit light of a third color, each of the plurality ofsecond pixels may further include a sixth LED configured to emit lightof the third color, and the optical resonance layer may be at the secondregion to correspond to the second LED, the fourth LED, and the sixthLED.

The optical resonance layer may include at least one of a hole transportmaterial, a hole injection material, an electron transport material, andan electron injection material.

A minor angle between the first region and the second region may be anobtuse angle.

The first region may have a polygonal shape having a plurality of edges,and the second region may be adjacent to at least one edge of theplurality of edges.

According to some example embodiments of the present invention, anelectrical device includes: a main body; and a display panel at one sideof the main body and configured to display an image through a screenthat is bent around at least one folding portion, wherein the displaypanel includes: a substrate comprising a first region and a secondregion that are adjacent to each other relative to the folding portion,wherein the second region is bent relative to the first region; aplurality of first pixels at the first region; a plurality of secondpixels at the second region; and an optical resonance layer at oneregion among the first region and the second region, wherein each of theplurality of first pixels and each of the plurality of second pixelscomprise a plurality of light-emitting diodes (LEDs) that producedifferent colors.

Each of the plurality of first pixels and each of the plurality ofsecond pixels may include a red LED, a green LED, and a blue LED, andthe optical resonance layer may be at the second region to correspond toat least one of the red LED, the green LED, and the blue LED of theplurality of second pixels.

Each of the LEDs may include a pixel electrode that is patterned incorrespondence to each of the LEDs, an emission layer at the pixelelectrode, and a counter electrode at the emission layer, and thecounter electrodes of the LEDs may be integrally formed to cover theemission layers of each of the plurality of LEDs.

Each of the plurality of LEDs may further include at least onefunctional layer between the pixel electrode and the counter electrode,and the at least one functional layers of the LEDs may be integrallyformed and located at the first and second regions to correspond to allof the plurality of LEDs.

The optical resonance layer may include at least one of a hole transportmaterial, a hole injection material, an electron transport material, andan electron injection material.

A first LED, which is one of the red LED, the green LED, and the blueLED of each of the plurality of first pixels, may have a first heightfrom the pixel electrode of the first LED to the emission layer of thefirst LED, a second LED may be one of the red LED, the green LED, andthe blue LED of each of the plurality of second pixels and may beconfigured to emit light of a same color with the first LED, may have asecond height from the pixel electrode the second LED to the emissionlayer of the second LED, and the first height and the second height maybe different from each other.

A thickness of the optical resonance layer may be equal to a differencebetween the first height and the second height.

The electrical device may further include a transparent protectivesubstrate at one side of the screen in the display panel, and thetransparent protective substrate may be bent in correspondence to thedisplay panel.

The first region may have a polygonal shape having a plurality of edgesand the second region may be adjacent to at least one edge of theplurality of edges.

Some aspects, characteristics, and features other than the descriptiondescribed above will be clarified by referring to drawings, claims, anddetailed descriptions provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become more apparent and more readilyappreciated from the following description of the example embodiments,taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic perspective view of an electrical device accordingto an example embodiment;

FIG. 2 is a schematic cross-sectional view of a first pixel and a secondpixel of a display device included in the electrical device of FIG. 1;

FIGS. 3 and 4 are each a schematic cross-sectional view of a displaydevice according to another example embodiment;

FIGS. 5 to 8 are cross-sectional views for describing a method ofmanufacturing a display device, according to an example embodiment;

FIG. 9 is a schematic perspective view of an electrical device accordingto another example embodiment; and

FIGS. 10A and 10B are each schematic perspective views of an electricaldevice according to another example embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to example embodiments, examples ofwhich are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present example embodiments may have different forms and should notbe construed as being limited to the descriptions set forth herein.Accordingly, the example embodiments are merely described below, byreferring to the figures, to explain aspects of the present description.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

In drawings, like reference numerals refer to like elements throughoutand overlapping descriptions shall not be repeated.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another.

As used herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

It will be understood that when a layer, region, or component isreferred to as being “formed on,” another layer, region, or component,it can be directly or indirectly formed on the other layer, region, orcomponent. That is, for example, intervening layers, regions, orcomponents may be present.

Sizes of elements in the drawings may be exaggerated for convenience ofexplanation. In other words, because sizes and thicknesses of componentsin the drawings are arbitrarily illustrated for convenience ofexplanation, the following embodiments are not limited thereto.

When a certain embodiment may be implemented differently, a specificprocess order may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order.

When films, regions, or components are connected to each other, thefilms, the regions, or the components may not only be directly connectedto each other, but may also be indirectly connected to each other asanother film, another region, or another component is disposedtherebetween.

As used herein, the term “substantially,” “about,” and similar terms areused as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art. Further, the use of “may” when describing embodiments of thepresent invention refers to “one or more embodiments of the presentinvention.” As used herein, the terms “use,” “using,” and “used” may beconsidered synonymous with the terms “utilize,” “utilizing,” and“utilized,” respectively. Also, the term “exemplary” is intended torefer to an example or illustration.

The electronic or electric devices and/or any other relevant devices orcomponents according to embodiments of the present invention describedherein may be implemented utilizing any suitable hardware, firmware(e.g. an application-specific integrated circuit), software, or acombination of software, firmware, and hardware. For example, thevarious components of these devices may be formed on one integratedcircuit (IC) chip or on separate IC chips. Further, the variouscomponents of these devices may be implemented on a flexible printedcircuit film, a tape carrier package (TCP), a printed circuit board(PCB), or formed on one substrate. Further, the various components ofthese devices may be may be a process or thread, running on one or moreprocessors, in one or more computing devices, executing computer programinstructions and interacting with other system components for performingthe various functionalities described herein. The computer programinstructions are stored in a memory which may be implemented in acomputing device using a standard memory device, such as, for example, arandom access memory (RAM). The computer program instructions may alsobe stored in other non-transitory computer readable media such as, forexample, a CD-ROM, flash drive, or the like. Also, a person of skill inthe art should recognize that the functionality of various computingdevices may be combined or integrated into a single computing device, orthe functionality of a particular computing device may be distributedacross one or more other computing devices without departing from thespirit and scope of the exemplary embodiments of the present invention.

FIG. 1 is a schematic perspective view of electronic equipment or anelectrical device according to an example embodiment.

Referring to FIG. 1, electronic equipment (or electrical device) 1includes a main body or housing 20 and a display device 10 (e.g., adisplay panel), wherein the main body 20 includes at least one opensurface and the display device 10 is positioned or arranged on the opensurface of the main body 20. The electronic equipment 1 may be portableelectronic equipment, such as a mobile phone and a tablet PC, but is notlimited thereto. For example, any equipment (or device), such as smalland medium-sized image advertising equipment or large-sized imageadvertising equipment, may be used as the electronic equipment 1 as longas the equipment is capable of providing an image.

The main body 20 includes at least one open surface, and the displaydevice 10 may be positioned or arranged on the open surface of the mainbody 20. In addition, various components such as a battery, acommunication terminal, etc., for driving or operating the displaydevice 10 may be mounted inside the main body 20.

The display device 10 may provide (e.g., display) an image for a user 2through a screen 4. The screen 4 may be bent relative to at least onefolding portion L. For example, the screen 4 may include a first screen4A and a second screen 4B that are positioned on both (e.g., opposite)sides relative to the folding portion L. The screen 4 may be bent suchthat a minor angle θ (e.g., a central angle) between the first screen 4Aand the second screen 4B is an obtuse angle. In addition, the firstscreen 4A includes a plurality of first pixels P1 to provide an image,and the second screen 4B includes a plurality of second pixels P2 toprovide an image.

Thus, the first screen 4A and the second screen 4B are bent relative toeach other, and thus a first distance L1 between a user 2 and an imageprovided from the first screen 4A is different from a second distance L2between a user 2 and an image provided from the second screen 4B. In anexample embodiment, the first screen 4A, which is relatively large, is amain screen while the second screen 4B, which is relatively small, is asub-screen. In this case, the second distance L2 may be longer than thefirst distance L1.

A transparent protective substrate 12 may be positioned on the screen 4of the display device 10, thereby protecting the screen 4 having aplurality of the first pixels P1 and a plurality of the second pixelsP2. The transparent protective substrate 12 may be formed of atransparent glass material, a transparent plastic material, or the like.The transparent protective substrate 12 may be also bent in accordancewith the screen 4, which is an emission surface in the display device10.

The first screen 4A and the second screen 4B may emit light in aperpendicular direction and an oblique direction with respect to anemission surface of each of the first screen 4A and the second screen4B. As shown in FIG. 1, when the first screen 4A is positioned inparallel with the user 2 (e.g., both eyes of a user), light emitted in aperpendicular direction with respect to the emission surface of thefirst screen 4A may be mainly recognized or perceived by the user 2.Because the second screen 4B is bent relative to the first screen 4A,the second screen 4B is positioned obliquely to the user 2, and thuslight emitted in an oblique direction with respect to the emissionsurface of the second screen 4B may not be mainly recognized orperceived by the user 2. Thus, although the first screen 4A and thesecond screen 4B provide an image of the same color, the colorcharacteristics provided by each of the first screen 4A and the secondscreen 4B are recognized differently by the user according to the screen4.

However, according to an embodiment, one of the first screen 4A and thesecond screen 4B of the display device 10 may further include an opticalresonance layer 230 (shown, for example, in FIG. 2). Accordingly, thedifference in color coordinates of light emitted from the first screen4A and the second screen 4B may be minimized or reduced, and the user 2may recognize substantially the same color regardless of whether thelight perceived by the user 2 is emitted at the first screen 4A or thesecond screen 4B.

FIG. 2 is a schematic cross-sectional view of one of the plurality offirst pixels P1 and one of the plurality of second pixels P2 of thedisplay device 10 of FIG. 1. In FIG. 2, the display device 10 isillustrated without including the transparent protective substrate 12for convenience of explanation.

Referring to FIG. 2, the display device 10 includes a substrate 100 onwhich the first pixel P1 and the second pixel P2 are formed. Thesubstrate 100 is bent according to a shape of the display device 10. Forexample, the substrate 100 includes a first region 11 and a secondregion 12, which are bent against each other, and the first region 11 ofthe substrate 100 corresponds to the first screen 4A of the displaydevice 10 and the second region 12 corresponds to the second screen 4Bof the display device 10.

The first pixel P1 is formed on the first region 11 of the substrate100, and the second pixel P2 is formed on the second region 12 of thesubstrate 100. Here, each of the first pixel P1 and the second pixel P2may include sub-pixels R1 R2, G1 G2, and B1 B2 that produce differentcolors from each other. For example, each of the first pixel P1 and thesecond pixel P2 may include the sub-pixels R1 R2, G1 G2, and B1 B2 thateach emit red light, green light, and blue light, respectively, whereineach of the sub-pixels R1 R2, G1 G2, and B1 B2 may includelight-emitting diodes, such as organic light-emitting diodes OLED 1,OLED 2, and OLED 3. An example embodiment of the present inventiveconcept describes that each of the first pixel P1 and the second pixelP2 includes the red, green, and blue sub-pixels R1 R2, G1 G2, and B1 B2,but the example embodiments of the present invention are not limitedthereto. In the case of a display device capable of producingfull-color, a combination of different colors other than a combinationof red, green, and blue may be available. That is, when a display deviceis capable of producing full-color, the display device may be configuredin various modifications in addition to the combination of the threecolor sub-pixels R1 R2, G1 G2, and B1 B2 as described in the exampleembodiment above. For example, a combination of four sub-pixels of blue,green, red, and white may be available.

The substrate 100 may be formed of a metal material or a plasticmaterial, such as polyethylen terephthalate (PET), polyethylennaphthalate (PEN), polyimide, or the like. When the substrate 100 isformed of such a plastic or metal material, the substrate 100 may haveflexibility. To prevent penetration of impurities or contaminants, thesubstrate 100 may include a buffer layer that is formed of SiO₂ and/orSiNx.

A pixel circuit (PC) may be formed, on the substrate 100, for each ofthe sub-pixels R1 R2, G1 G2, and B1 B2. The PC may include a thin filmtransistor and a capacitor, and may be covered by an insulating layer150 of which a top surface is approximately flat.

A pixel electrode 210 is formed in an island shape or configuration asbeing patterned in correspondence to each of the sub-pixels R1 R2, G1G2, and B1 B2. The pixel electrode 210 may be formed as a reflectiveelectrode or a (semi)transparent electrode. When the pixel electrode 210is formed as a reflective electrode, silver (Ag), magnesium (Mg),aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni),neodymium (Nd), iridium (Ir), chromium (Cr), or a compound thereof maybe used to form a reflective layer to which a layer formed of indium tinoxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide(In₂O₃), indium gallium oxide (IGO) or aluminum zinc oxide (AZO) may beformed. When the pixel electrode 210 is formed as a (semi)transparentelectrode, the (semi)transparent electrode may be formed of ITO, IZO,ZnO, IGO, or AZO.

A pixel-defining film 180 may include an opening in correspondence tothe sub-pixels R1 R2, G1 G2, and B1 B2, and may expose a top surface ofthe pixel electrode 210 through the opening. The pixel-defining film 180may also cover an edge of the pixel electrode 210. The pixel-definingfilm 180 may include an organic insulating layer, such as an acrylresin. The pixel-defining film 180 increases a distance between one endof the pixel electrode 210 and a counter electrode 240, therebypreventing or reducing the occurrence of arc or the like at one end ofthe pixel electrode 210.

The sub-pixels R1 R2, G1 G2, and B1 B2 include emission layers 223R,223G, and 223B, respectively. The red sub-pixel R1 of the first pixel P1and the red sub-pixel R2 of the second pixel P2 may each include a redemission layer 223R. For example, the red emission layer 223R mayinclude, as a host, an anthracene-based derivative, a carbazole-basedcompound, or the like, and may include, as a dopant, a phosphorescentmaterial including at least one selected from the group consisting ofPIQIr (acac)(bis(1-phenylisoquinoline)acetylacetonate iridium), PQIr(acac(bis(1-phenylquinoline)acetylacetonate iridium), PQIr(tris(1-phenylquinoline) iridium), and PtPEP (octaethylporphyrinplatinum). In another example embodiment, the red emission layer 223Rmay include a fluorescent material, such as PED:Eu(DBM)3(Phen) orPerylene, but is not limited thereto.

The green sub-pixel G1 of the first pixel P1 and the green sub-pixel R2of the second pixel P2 may include each a green emission layer 223G. Forexample, the green emission layer 223G may include, as a host, ananthracene-based derivative, a carbazole-based compound, or the like,and may include, as a dopant, Ir(ppy)3 (fac tris(2-phenylpyridine)iridium). In another example embodiment, the green emission layer 223Gmay include a fluorescent material, such as Alq₃(tris(8-hydroxyquinoline) aluminum), but is not limited thereto.

The blue sub-pixel B1 of the first pixel P1 and the blue sub-pixel B2 ofthe second pixel P2 may each include a blue emission layer 223B. Forexample, the blue emission layer 223B may include, as a host, ananthracene-based derivative, a carbazole-based compound, or the like,and may include, as a dopant, F₂Irpic, (F2ppy)₂Ir(tmd) or Ir(dfppz)₃. Inanother example embodiment, the blue emission layer 223B may include afluorescent material including at least one selected from the groupconsisting of DPVBi, spiro-DPVBi, spiro-6P, distilled benzene (DSB),distilled arylene (DSA), a PFO-based polymer, and a PPV-based polymer,but is not limited thereto.

At least one functional layer of a first functional layer 220 a and asecond functional layer 220 b may be further formed on and/or underneaththe red, green, and blue emission layers 223R, 223G, and 223B that areeach formed on the red, green, and blue sub-pixels R1 R2, G1 G2, and B1B2.

The first functional layer 220 a is arranged or formed adjacent to thepixel electrode 210, and may be formed as one body to cover the firstregion 11 and the second region 12 of the substrate 100. The firstfunctional layer 220 a may include a hole transport layer (HTL) 222 anda hole injection layer (HIL) 221, and may have a single-layer structureor a multi-layer structure. For example, when the first functional layer220 a is formed of a high-molecular weight material, the firstfunctional layer 220 a may serve as the HTL 222 and includepoly-(3,4)-ethylene-dihydroxy thiophene (PEDOT) or polyaniline (PANI).When the first functional layer 220 a is formed of a low-molecularweight material, the first functional layer 220 a may include both theHIL 221 and the HTL 222.

The second functional layer 220 b may be arranged or formed over each ofthe emission layers 223R, 223G, and 223B, and may be formed as one bodyto cover the first region 11 and the second region 12 of the substrate100. The second functional layer 220 b may include an electron transportlayer (ETL) 224 and an electron injection layer (EIL) 225. The formationof the second functional layer 220 b may be omitted in some exampleembodiments. For example, when the first functional layer 220 a and theemission layers 223R, 223G, and 223B are formed of a high-molecularweight material, the second functional layer 220 b may be omitted. Whenthe first functional layer 220 a and the emission layers 223R, 223G, and223B are formed of a low-molecular weight material, the secondfunctional layer 220 b may be formed to enhance light-emittingcharacteristics.

The optical resonance layer 230 is formed on the second region 12 amongthe first region 11 and the second region 12 of the substrate 100. Asthe optical resonance layer 230 is formed only on the second region 12of the substrate 100, the difference in the color characteristics causedby the bending between the first screen 4A and the second screen 4B maybe improved as described above.

The optical resonance layer 230 is positioned between the pixelelectrode 210 and the counter electrode 240, and may be formed on thesecond region 12 only among the first region 11 and the second region 12of the substrate 100. In one embodiment, the optical resonance layer 230may be formed between the pixel electrode 210 and the emission layers223R, 223G, and 223B of the second region 12 of the substrate 100. Aheight from the pixel electrode 210 to each of the emission layers 223R,223G, and 223B of the sub-pixels R1, G1, and B1 of the first pixel P1 isdifferent from a height from the pixel electrode 210 to each of theemission layers 223R, 223G, and 223B of the sub-pixels R2, G2, and B2 ofthe second pixel P2.

In an example embodiment, a first height H1 from the pixel electrode 210of the red sub-pixel R1 of the first pixel P1 to the red emission layer223R may be smaller than a second height from the pixel electrode 210 ofthe red sub-pixel R2 of the second pixel P2 to the red emission layer223R. In another example embodiment, a third height H3 from the pixelelectrode 210 of the green sub-pixel G1 of the first pixel P1 to thegreen emission layer 223G may be smaller than a fourth height H4 fromthe pixel electrode 210 of the green sub-pixel G2 of the second pixel P2to the green emission layer 223G. Likewise, a fifth height from thepixel electrode 210 of the blue sub-pixel B1 of the first pixel P1 tothe blue emission layer 223B may be smaller than a sixth height measuredfrom the pixel electrode 210 of the blue sub-pixel B2 of the secondpixel P2 to the blue emission layer 223B. A difference between the firstheight H1 and the second height H2, a difference between the thirdheight H3 and the fourth height H4, and/or a difference between thefifth height H5 and a sixth height H6 may be substantially the same as athickness of the optical resonance layer 230.

FIG. 2 illustrates an example embodiment that the optical resonancelayer 230 is located underneath each of the emission layers 223R, 223G,and 223B of each of the sub-pixels R2, G2, and B2 of the second region12 of the substrate 100, but the example embodiment is not limitedthereto. In another example embodiment, the optical resonance layer 230may be arranged over each of the emission 223R, 223G, and 223B of eachof the sub-pixels R2, G2, and B2 of the second region 12 of thesubstrate 100.

The optical resonance layer 230 may perform a role of at least one of aHIL, a HTL, an ETL, and an EIL. In an example embodiment, the opticalresonance layer 230 may be formed of a hole transport material, andaccordingly, may perform a role of the HTL. The hole transport materialmay be, for example, a carbazole-based derivatice, such asN-phenylcarbazole or polyvinylcarbazole, a triphenylamin-based material,such asN,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine(TPD), N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB), or4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), but is not limitedthereto.

In another example embodiment, the optical resonance layer 230 may beformed of a hole injection material, and accordingly, may perform a roleof the HIL. The hole injection material may be, for example, aphthalocyanine compound, such as copper phthalocyanine, orN,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine(DNTPD), 4,4′,4″-tris(3-methylphenylphenylamino) triphenylamine(m-MTDATA), 4,4′4″-tris(N,N-diphenylamino)triphenylamine (TDATA),4,4′,4″-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine (2T-NATA),N,N′-di(-naphthyl)-N,N′-diphenylbenzidine (NPB),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA), polyaniline/camphorsulfonic acid (Pani/CSA), or polyaniline/poly(4-styrenesulfonate)(PANI/PSS), but is not limited thereto.

In another example embodiment, the optical resonance layer 230 may beformed of an electron injection material, and accordingly, may perform arole of the EIL. The electron injection material may be, for example,LiF, NaCl, CsF, Li2O, or BaO, but is not limited thereto

In another example embodiment, the optical resonance layer 230 may beformed of an electron transport material, and accordingly, may perform arole of the HTL. The electron transport material may be, for example,Alq₃, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-diphenyl-1,10-phenanthroline (Bphen),3-(4-Biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ),4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ),2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD),bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum(BAIq), beryllium bis(benzoquinolin-10-olate) (Bebq₂),9,10-di(naphthalene-2-yl)anthrascene (AND), or the like, but is notlimited thereto.

Among the sub-pixels R1, G1, B1, R2, G2, and B2 that are formed over thefirst pixel P1 and the second pixel P2, the sub-pixels R1 R2, G1 G2, andB1 B2 that produce at least one color may further include a resonanceauxiliary layer. The optical resonance layer 230 is configured to reducethe color deviation in accordance with the arrangement of the firstscreen 4A and the second screen 4B, whereas a first resonance auxiliarylayer 231 and a second resonance auxiliary layer 232 are configured toimprove light-emitting efficiency of a particular color.

In a non-limiting example embodiment, the red sub-pixels R1 and R2 mayeach further include the first resonance auxiliary layer 231 that isformed underneath the red emission layer 223R, so as to improvelight-emitting efficiency of red light, and the green sub-pixels G1 andG2 may each further include the second resonance auxiliary layer 232that is formed underneath the green emission layer 223G, so as toimprove light-emitting efficiency of green light. The first resonanceauxiliary layer 231 and the second resonance auxiliary layer 232 may beeach independently used to amplify light having a different wavelength,and thus a thickness of each of the first resonance auxiliary layer 231and the second resonance auxiliary layer 232 may be different from eachother.

The counter electrode 240 may be integrally formed as one bodycorresponding to the first electrode P1 and the second electrode P2, soas to cover the first region 11 and the second region 12 of thesubstrate 100. The counter electrode 240 may be formed as a(semi)transparent electrode or a reflective electrode. When the counterelectrode 240 is formed as a (semi)transparent electrode, a layer formedof Li, Ca, LiF/Ca, LiF/Al, Al, Mg, or a combination thereof is formed,and then, a layer formed of a (semi)transparent material, such as ITO,IZO, ZnO, or In₂O₃, is formed thereon, thereby forming a(semi)transparent electrode. When the counter electrode 240 is formed asa reflective electrode, a layer including at least one material selectedfrom, e.g., Li, Ca, LiF/Ca, LiF/Al, Al, Ag, and Mg may be formed,thereby forming a reflective electrode. Although not shown, a protectivelayer may be further formed on the counter electrode 240.

FIGS. 3 and 4 are each a schematic cross-sectional view of a displaydevice according to another example embodiment.

The optical resonance layer 230 is formed on the second region 12 onlyamong the first region 11 and the second region 12 of the substrate 100.As shown in FIG. 2, the optical resonance layer 230 may be formed tocorrespond to the red, green, and blue sub-pixels R2, G2, and B2 thatconstitute the second pixel P2 on the second region 12.

In another example embodiment, referring to FIG. 3, the opticalresonance layer 230 may be formed on the second region 12 only of thesubstrate 100, but may correspond to only two sub-pixels, e.g., the redand green sub-pixels R2 and G2, among the red, green, and bluesub-pixels R2, G2, and B2 that constitute the second pixel P2.

In another example embodiment, referring to FIG. 4, the opticalresonance layer 230 may be formed on the second region 12 only of thesubstrate 100, but may correspond to only 1 sub-pixel, e.g., the redsub-pixel R2, among the red, green, and blue sub-pixels R2, G2, and B2that constitute the second pixel P2.

FIGS. 5 to 8 are cross-sectional views for describing a method ofmanufacturing the display device, according to an example embodiment.

Referring to FIG. 5, a substrate 100′ including the first region 11 andthe second region 12 is prepared. Here, the substrate 100′ is a flatsubstrate in which the first region 11 and the second region 12 are notbent with respect to each other. The substrate 100′ may be formed of ametal material or a plastic material as described above.

A buffer layer that prevents or reduces penetration of impurities orcontaminants may be formed on the substrate 100′, and a pixel-circuit(PC) including a thin film transistor and a capacitor may be formed onthe buffer layer. The PC is formed for each of the sub-pixels R1, G1,B1, R2, G2, and B2, and may be covered by an insulating layer 150 ofwhich a top surface is approximately flat.

Afterwards, the pixel electrode 210 is formed on the insulating layer150, and the pixel-defining film 180 exposing a top surface of the pixelelectrode 210 is formed of the pixel electrode 210. The pixel electrode210 is formed for each of the sub-pixels R1 R2, G1 G2, and B1 B2, andmay be formed as a (semi)transparent electrode or a reflectiveelectrode. Materials for forming the pixel electrode 210 and thepixel-defining film 180 are the same with those described above inconnection with FIG. 2.

Referring to FIG. 6, the first functional layer 220 a may be formed onthe substrate 100′. The first functional layer 220 a may be formed asone body to cover the first region 11 and the second region 12 of thesubstrate 100′. The first functional layer 220 a may include the HTL 222and the HIL 221, and may have a single-layer structure or a multi-layerstructure. Materials for forming the first functional layer 220 a arethe same with those described above in connection with FIG. 2.

Afterwards, the optical resonance layer 230 is formed on the secondregion 12 among the first region 11 and the second region 12 of thesubstrate 100′. In some example embodiments, an optical resonance layermay be formed by a thermal evaporation method using a mask including anopening, which is arranged in correspondence to the second region 12 ofthe substrate 100′. Here, a case where the optical resonance layer 230is formed by using the thermal evaporation method is described, but thepresent invention is not limited thereto.

The optical resonance layer 230 may include, for example, at least oneselected from a hole injection material, a hole transport material, anelectron injection material, and an electron transport material, and mayhave a single-layer structure or a multi-layer structure. The opticalresonance layer 230 may have a thickness in a range of 80 Å to 210 Å (orabout 80 Å to about 210 Å).

FIG. 6 illustrates a case where the optical resonance layer 230 isformed to correspond to all of the sub-pixels R2, G2, and B2 of thesecond pixel P2, but the present invention is not limited thereto. Asdescribed in connection with FIGS. 3 and 4, the optical resonance layer230 may be formed to correspond to at least one sub-pixel of theplurality of the sub-pixels R2, G2, and B2 of the second pixel P2.

Referring to FIG. 7, the emission layers 223R, 223G, and 223B are formedfor each of the sub-pixels R1, G1, B1, R2, G2, and B2. On the firstregion 11 and the second region 12 of the substrate 100′, the redemission layer 223R is formed on a region corresponding to the redsub-pixels R1 and R2, the green emission layer 223G is formed on aregion corresponding to the green sub-pixels G1 and G2, and the blueemission layer 223B is formed on a region corresponding to the bluesub-pixels B1 and B2. The emission layers of the same color 223R, 223G,and 223B may be formed at the same time according to the same processfor each of the sub-pixels R1, G1, B1, R2, G2, and B2. The red emissionlayer 223R, the green emission layer 223G, and the blue emission layer223B may be formed of a phosphorescent material or a fluorescentmaterial as described in connection with FIG. 2.

Before performing the process of forming the emission layers 223R, 223G,and 223B, a resonance auxiliary layer may be formed on a regioncorresponding to at least one of the sub-pixels R1, G1, B1, R2, G2, andB2. For example, before performing the process of forming the redemission layer 223R, a first resonance auxiliary layer 231 may beformed, and before performing the process of forming the green emissionlayer 223G, a second resonance auxiliary layer 232 may be formed. Forexample, the first resonance auxiliary layer 231 and the secondresonance auxiliary layer 232 may include at least one of a holeinjection material, a hole transport material, an electron injectionmaterial, and an electron transport material.

Referring to FIG. 8, the second functional layer 220 b and the counterelectrode 240 are formed on the substrate 100′. The second functionallayer 220 b may be formed as one body to cover the first region 11 andthe second region 12 of the substrate 100′. The second functional layer220 b may include the EIL 225 and the ETL 224, and materials for formingthe second functional layer 220 b are the same with those describedabove in connection with FIG. 2. In a non-limiting example embodiment,the second functional layer 220 b may be omitted.

The counter electrode 240 may be formed as one body to cover the firstregion 11 and the second region 12 of the substrate 100′. The counterelectrode 240 may be formed as a (semi)transparent electrode or areflective electrode, and materials for forming the counter electrode240 are the same with those described above in connection with FIG. 2.

Afterwards, the substrate 100′ is subjected to bending to have a shapeas shown in FIG. 1, and that is, the first region 11 and the secondregion 12 are arranged on both (e.g., opposing) sides of the foldingportion L (see FIG. 1).

A display device 10 includes the optical resonance layer 230 on thesecond region 12, and thus may improve the difference in the colorcoordinates caused by the bending between the first screen 4A formed incorrespondence to the first region 11 of the substrate 100 and thesecond screen 4B formed in correspondence to the second region 12 of thesubstrate 100.

Table 1 below shows color coordinates of a first screen 4A and a secondscreen 4B of a display device 10 in which an optical resonance layer 230is not formed, whereas Table 2 below shows color coordinates of thefirst screen 4A and the second screen the display device 10 in which theoptical resonance layer 230 is formed on the second region 12 of thesubstrate 100 according to the example embodiments of the presentinventive concept. In Tables 1 and 2, θ denotes a minor angle betweenthe first screen 4A and the second screen 4B (see FIG. 1), x and y eachdenote an x-axis value and an y-axis value of the color-coordinategraph, and R, G, and B each denote red light, green light, and bluelight.

TABLE 1 Second screen First screen θ = 120° θ = 135° θ = 150° x y x y xy x y R 0.677 0.323 0.664 0.336 0.655 0.344 0.654 0.346 G 0.270 0.6950.219 0.717 0.197 0.703 0.205 0.689 B 0.139 0.046 0.146 0.035 0.1490.032 0.148 0.034

TABLE 2 Second screen First screen θ = 120° θ = 135° θ = 150° x y x y xy x y R 0.677 0.323 0.674 0.326 0.669 0.330 0.666 0.333 G 0.270 0.6950.267 0.695 0.262 0.695 0.252 0.687 B 0.139 0.046 0.138 0.050 0.1380.052 0.141 0.050

Referring to Table 1 above, in the case of the display device 10 inwhich the optical resonance layer 23 is not formed, the difference inthe color coordinates of the first screen 4A and the second screen 4B isabout 0.072 in maximum according to the angle between the first screen4A and the second screen 4B. However, referring to Table 2 above, in thecase of the display device 10 in which the optical resonance layer 23 isformed, the difference in the color coordinates of the first screen 4Aand the second screen 4B is decreased to about 0.011 in maximum even inconsideration of the angle between the first screen 4A and the secondscreen 4B.

In some example embodiments, FIG. 1 illustrates an example embodiment ofthe display device 10 that is bent such that a first distance L1 betweena user 2 and an image provided through the first screen 4A is smallerthan a second distance L2 a user 2 and an image provided through thesecond screen 4B, but the example embodiment is not limited thereto.

In some other example embodiments, FIG. 9 illustrates an exampleembodiment of the display device 10 that is bent to have an obtuse minorangle θ between the first screen 4A and the second screen 4B such that afirst distance L1 between a user 2 and an image provided through thefirst screen 4A is greater than a second distance L2 a user 2 and animage provided through the second screen 4B. The display device 10included in electronic equipment 1 of FIG. 9 may have a structure asdescribed be referring to FIG. 1. Accordingly, the display device 10 mayminimize the difference in the color coordinates of the first screen 4Aand the second screen 4B, and may improve the efficiency of lightemitted from the second screen 4B.

FIGS. 10A and 10B are each schematic perspective views of electronicequipment according to another example embodiment.

According to the example embodiments described above, the second screen4B is positioned on one side of the first screen 4A, but the exampleembodiments are not limited thereto. In some example embodiments, asdescribed in the FIGS. 10A and 10B, two second screens 4B may be formedboth sides of the first screen 4A. The minor angles between the firstscreen 4A and the second screens 4B may be obtuse angles θ1 and θ2, andthe obtuse angle θ1 and the obtuse angle θ2 may be different from eachother.

According to the example embodiments described above, the second screens4B are positioned on one side or both sides of the first screen 4A, butthe example embodiments are not limited thereto.

The first screen 4A may have a polygonal shape having a plurality ofedges, and the second screen 4B may be adjacent to at least one of theplurality of edges of the first screen 4A. The at least one of theplurality of edges of the first screen 4A may correspond to the foldingportion L. For example, in a non-limiting example embodiment, when thefirst screen 4A is a quadrangle, the second screens 4B may be positionedon both sides, an upper side, and a lower side of the first screen 4A.

According to the example embodiments described above, the foldingportion is formed as a line type, but the example embodiments are notlimited thereto. In some example embodiments, the folding portion L maybe a band type. When the folding portion L is a line type, the first andsecond screens 4A and 4B are sharply bent relative to each other. Whenthe folding portion L is a band type, the first and second screens 4Aand 4B are smoothly bent relative to each other to form a smooth curve.

As described above, according to the one or more of the above exampleembodiments, there are provided a display device having a bent screenwith uniform color characteristics, and electronic equipment using thedisplay device.

It should be understood that example embodiments described herein shouldbe considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exampleembodiment should typically be considered as available for other similarfeatures or aspects in other example embodiments.

While one or more example embodiments have been described with referenceto the figures, it will be understood by those of ordinary skill in theart that various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims,and their equivalents.

What is claimed is:
 1. A display device comprising: a substratecomprising a first region and a second region bent relative to the firstregion; a plurality of first pixels at the first region, each of thefirst pixels comprising a first light-emitting diode (LED), the firstLED comprising a pixel electrode, a functional layer, an emission layerfor emitting light of a first color, and a counter electrode insequential order; and a plurality of second pixels at the second region,each of the second pixels comprising a second LED, the second LEDcomprising a pixel electrode, a functional layer, an emission layerconfigured to emit light of the first color, and a counter electrode insequential order, wherein the second LED further comprises an opticalresonance layer between the pixel electrode and the emission layer,wherein the optical resonance layer is not present within the pluralityof first pixels in the first region, and wherein a number of layersbetween the pixel electrode and the emission layer of the second LED isgreater than that between the pixel electrode and the emission layer ofthe first LED.
 2. The display device of claim 1, wherein the counterelectrode of the first LED is integrally formed with the counterelectrode of the second LED to cover the first region and the secondregion of the substrate.
 3. The display device of claim 1, wherein thefunctional layer corresponding to the first LED is integrally formedwith the functional layer corresponding to the second LED.
 4. Thedisplay device of claim 1, wherein a first height from the pixelelectrode of the first LED to the emission layer of the first LED issmaller than a second height from the pixel electrode of the second LEDto the emission layer of the second LED.
 5. The display device of claim4, wherein a thickness of the optical resonance layer is equal to adifference between the first height and the second height.
 6. Thedisplay device of claim 1, wherein each of the first LED and the secondLED further comprises a first resonance auxiliary layer between thepixel electrode and the emission layer, respectively.
 7. The displaydevice of claim 6, wherein each of the first pixels further comprises athird LED configured to emit light of a second color, wherein each ofthe second pixels further comprises a fourth LED configured to emitlight of the second color, wherein each of the third LED and the fourthLED further comprises a pixel layer, an emission layer configured toemit light of the second color, and a second resonance auxiliary layerbetween the pixel layer and the emission layer, respectively, andwherein a thickness of the first resonance auxiliary layer is differentfrom a thickness of the second resonance auxiliary layer.
 8. The displaydevice of claim 1, wherein each of the first pixels further comprises athird LED for emitting light of a second color, wherein each of thesecond pixels further comprises a fourth LED for emitting light of thesecond color, and wherein the optical resonance layer corresponds to thesecond LED and the fourth LED.
 9. The display device of claim 8, whereineach of the third LED and the fourth LED further comprises a pixellayer, an emission layer configured to emit light of the second color,and a second resonance auxiliary layer between the pixel layer and theemission layer, respectively.
 10. The display device of claim 8, whereineach of the first pixels further comprises a fifth LED configured toemit light of a third color, wherein each of the second pixels furthercomprises a sixth LED configured to emit light of the third color, andwherein the optical resonance layer corresponds to the second LED, thefourth LED, and the sixth LED.
 11. The display device of claim 1,wherein the optical resonance layer comprises at least one of a holetransport material, a hole injection material, an electron transportmaterial, and an electron injection material.
 12. The display device ofclaim 1, wherein a minor angle between the first region and the secondregion is an obtuse angle.
 13. The display device of claim 1, whereinthe first region has a polygonal shape having a plurality of edges, andwherein the second region is adjacent to at least one edge of theplurality of edges.
 14. An electrical device comprising: a main body;and a display panel at one side of the main body and configured todisplay an image through a screen that is bent around at least onefolding portion, wherein the display panel comprises: a substratecomprising a first region and a second region that are adjacent to eachother relative to the folding portion, wherein the second region is bentrelative to the first region; a plurality of first pixels at the firstregion; a plurality of second pixels at the second region; and anoptical resonance layer between a pixel electrode and a counterelectrode facing the pixel electrode at only one region of the firstregion and the second region, wherein a number of layers between thepixel electrode and the counter electrode at the only one region isdifferent from a number of layers between a pixel electrode and acounter electrode at the other region, and wherein each of the firstpixels and each of the second pixels comprise a plurality oflight-emitting diodes (LEDs) that produce different colors.
 15. Theelectrical device of claim 14, wherein each of the first pixels and eachof the second pixels comprises a red LED, a green LED, and a blue LED,and wherein the optical resonance layer is at the second region tocorrespond to at least one of the red LED, the green LED, and the blueLED of the second pixels.
 16. The electrical device of claim 15, whereineach of the LEDs comprises a pixel electrode that is patterned incorrespondence to each of the LEDs, an emission layer at the pixelelectrode, and a counter electrode at the emission layer, and whereinthe counter electrodes of the LEDs are integrally formed to cover theemission layers of each of the plurality of LEDs.
 17. The electricaldevice of claim 16, wherein each of the plurality of LEDs furthercomprises at least one functional layer between the pixel electrode andthe counter electrode, and wherein the at least one functional layer ofthe LEDs is integrally formed and located at the first and secondregions to correspond to all of the, plurality of LEDs.
 18. Theelectrical device of claim 16, wherein the optical resonance layercomprises at least one of a hole transport material, a hole injectionmaterial, an electron transport material, and an electron injectionmaterial.
 19. The electrical device of claim 16, wherein a first LED,which is one of the red LED, the green LED, and the blue LED of thefirst pixels, has a first height from the pixel electrode of the firstLED to the emission layer of the first LED, wherein a second LED, whichis one of the red LED, the green LED, and the blue LED of the secondpixels, and which is configured to emit light of a same color as thefirst LED, has a second height from the pixel electrode the second LEDto the emission layer of the second LED, and wherein the first heightand the second height are different from each other.
 20. The electricaldevice of claim 19, wherein a thickness of the optical resonance layeris equal to a difference between the first height and the second height.21. The electrical device of claim 14, further comprising a transparentprotective substrate at one side of the screen in the display panel,wherein the transparent protective substrate is bent in correspondenceto the display panel.
 22. The electrical device of claim 14, wherein thefirst region has a polygonal shape having a plurality of edges, andwherein the second region is adjacent to at least one edge of theplurality of edges.